This is a 5-year training program renewal to support 5 postdoctoral trainees (Ph.D. and/or M.D.), 4 predoctoral students (Ph.D. or M.D./Ph.D) and 3 short-term minority (BS or in MS program) students per year for years 21-25 with an emphasis on a multidisciplinary approach to understanding hematopoietic cell regulation and disease mechanisms. The average training period for postdoctoral and predoctoral students will be 3 and 4 years, respectively. Twenty-three productive preceptors will provide extensive training in highly active and interactive research laboratories pursuing state of the art research on fundamental aspects of hematological, cellular, physiological, molecular, and biochemical aspects of cell growth and disease-related abnormalities. Preceptors are in 6 departments and 4 research centers housed in 4 buildings in close-proximity to each other. Strong track-records of peer-reviewed publications and extramural funding of preceptors are a major strength of the proposed training program, as are the training records of the preceptors. Opportunities for pursing multi-disciplinary research exist due to active, ongoing scientific collaborations among preceptors. A significant emphasis is to promote and foster the development of the next generation of biomedical researchers committed to scientific careers in academic medicine to become independent investigators. The approach for comprehensive training encompasses close and direct contact with seminars, laboratory meetings, and participation in national and international scientific meetings is already in place. The decision of a student to associate with a laboratory will be by mutual consent of trainee and preceptor. The scientiifc development of the trainee will be facilitiated by a research committee composed of preceptors with multi-disciplinary research interests. Major resources that are available include internationally recognized clinical and basic science research programs, an NCI-designated cancer center, an NIH-designated National Gene Vector Laboratory, an NIDDK Center of Excellence in Molecular Hematology, and state-of-the-art infrastructure, and frequent contacts with active investigators at IU and throughout the world